dmapool: speedup DMAPOOL_DEBUG with init_on_alloc

Avoid double-memset of the same allocated memory in dma_pool_alloc() when
both DMAPOOL_DEBUG is enabled and init_on_alloc=1.

Link: https://lkml.kernel.org/r/[email protected]
Fixes: 2d55c16 ("dmapool: create/destroy cleanup")
Signed-off-by: Tony Battersby <[email protected]>
Signed-off-by: Keith Busch <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

Author: abattersby

mm/dmapool.c

@@ -356,7 +356,7 @@ void *dma_pool_alloc(struct dma_pool *pool, gfp_t mem_flags,
 			break;
 		}
 	}
-	if (!(mem_flags & __GFP_ZERO))
+	if (!want_init_on_alloc(mem_flags))
 		memset(retval, POOL_POISON_ALLOCATED, pool->size);
 #endif
 	spin_unlock_irqrestore(&pool->lock, flags);